Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Gain access to PCB (use Insulation Mat as required)

Measurement:

Measure the resistance between pin 5 and 7
(grey wires) on X4 connector.
Resistance should be open circuit.
Notes:
1. Remember if a white PCB is fitted X4 is in a different position.
2. Colour of wires may differ but pins will be in same location.